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As I have explained before, water molecules due to their atomic makeup have one end with a partial negative charge (where the oxygen atom is) and another end with a partial positive charge (where the hydrogen atoms are). This gives rise to a phenomenon called surface tension where water molecules stick to each other (positive to negative) and to surfaces. This effect can be seen in the video below when I poured milk into my coffee before breakfast. The milk, which is more than 90% water, stuck to the side of the glass, and even thought I was tilting the glass more than 80 degrees, not a single drop of milk fell outside! In case you are wondering, as in my previous Science Before Breakfast video, I had scrambled eggs with bacon and home fries for breakfast but no blueberry toast this time.
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Plants are made up of 90-95% water, and water plays many roles in the physiology and chemistry of plants. Water is taken up by the roots and released by the leaves in a process called transpiration. Plants provide structural support for their non woody parts by using water to generate an internal pressure called turgor pressure. When water is scarce during, for example, a drought, turgor pressure diminishes, the plant loses rigidity, and its leaves and stems collapse. This process is called wilting. If wilting goes on for too long, a plant can die. In the left panel of the image below, my coleus plant experienced wilting on a very hot day. Coleus plants are not particularly drought tolerant, and being on a pot and not watered adequately made it worse. However, within one hour of watering, the coleus plant regained its health (right panel).  Whereas the movement of the leaves and stems during the process of wilting and the recovery phase are slow, plants can also change the turgor pressure of some of its parts very fast achieving rapid movements such as it the case of the Touch Me Not plant and the Venus flytrap. People that ride the rides in amusement parks seldom think of all the complex science that goes into designing these rides. The design of amusement park rides is a tour de force of concepts that you were exposed to in your high school physics class such as centripetal force, inertia, potential and kinetic energy, momentum, mass, and friction, to name a few. In many amusement park rides the human body gets accelerated and decelerated continuously often in many directions. This has effects on blood flow, the skeleton, the muscles, and the internal organs. Ride designers must take into account not just how the ride’s forces can affect the physiology of bodies of different sizes, shapes, and ages, but also how the body reacts to the forces of the ride. Failing to do so can result in injury or death. Most serious amusement park accidents are produced by a disregard of the safety rules by operators or lack of preventive maintenance of the equipment, and there have been several high profile amusement park accidents that have led to fatalities. However, the most common injuries are non-fatal such as head, neck, and back injuries, but some injuries occur as a result of the rider having a preexisting condition. In 2016, out of the 335 million people who visited amusement parks in the United States, it is estimated that about 30,000 sustained injuries severe enough to require a visit to the emergency room. The video below shows a ride called Khaos at the Montgomery County Fair in Maryland. This ride is a pendulum-type ride which produces a feeling of weightlessness in the rider during the upswing. Warm air contains water vapor which is invisible, and warm air is less dense so it tends to rise. As the air rises, the temperature and pressure decreases. This progressively lowers the capacity of the rising air to hold water vapor until a point is reached (called the dew point) at a certain altitude where the water vapor in the air transitions to the liquid state forming minuscule water droplets. If enough of these water droplets are present, the water in the air will not be invisible anymore and will acquire a white color forming what we call a cloud. If the water droplets become larger, the cloud acquires a grey color. The air can continue to rise pushing the top of clouds to great altitudes and making them look fluffy with a lot of dome-like bumps. If the layer of air below the clouds is free of turbulence, the point at which the transition from water vapor to water droplets occurs will be located at more or less the same altitude over a large area of land, Because of this, all the clouds over this area will seem to have a more or less uniform flat bottom located at the same altitude. In the video below, you can see many clouds with fluffy tops which have flat bottoms located at roughly the same altitude, as though all of them were resting on an even surface.  I saw this cool fossil at the Museum of Natural History in the city of Prague in the Czech Republic. The large fossil (left panel) is that of a plant whose scientific name is Cordaites borassifolius. The plant was part of a tropical forest that was covered by ash during the eruption of a volcano 309 million years ago in what is now the Ore Mountains in Central Europe. What is remarkable about the fossil is the well-preserved impression of a spider (white arrow in left panel, and right panel) that was on one of the leafs of the plant when they both perished during the eruption. The spider was identified as a species of Palaranea borassifoliae. Both the plant and the spider are now extinct and only found as fossils. The pictures belong to the author and can be used with permission. |
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